The present invention relates generally to power tools employing batteries to power various tool functions, and more specifically to battery-tool connections.
A preferred type of tool suitable with the present invention is portable, such as a combustion-powered fastener driving tool, also commonly referred to as a combustion tool or combustion nailer. Tools of this kind are manufactured by Illinois Tool Works, Inc. of Glenview, Ill. and are described in commonly assigned patents U.S. Pat. Nos. 4,552,162; 4,483,473; 4,483,474; 4,403,722 and 6,176,412, all of which are incorporated by reference herein.
Generally, combustion tools incorporate a housing enclosing a small internal combustion engine. The engine is powered by a canister of pressurized fuel gas, also called a fuel cell. A powerful, battery-powered electronic power distribution unit produces the spark for ignition, and a fan located in the combustion chamber provides both an efficient combustion within the chamber, and facilitates scavenging, including the exhaust of combustion by-products. The engine includes a reciprocating piston with an elongate, rigid driver blade disposed within a cylinder. Such tools include electronic control systems, spark generators, electric fan motors, and other electronic components, and are powered by batteries.
Conventional power tool batteries are preferably rechargeable and have a pair of electronic contacts positioned such that when the battery is fully inserted into the tool, they are physically connected to a pair of tool contacts, resulting in the battery being electronically connected to the tool.
In addition, conventional power tool batteries are configured for releasably locking into place when electronically connected to a corresponding power tool. The combination of the connection between the electronic contacts and the locking engagement is designed to maintain operation of the tool when subject to environmental stress and operational shock impacts that potentially cause disconnection and/or power disruption. However, conventional battery/tool connections are not always effective. Thus, one design criterion of such battery-tool connection is the ability to maintain the electronic connection while withstanding environmental stress and operational shock impact forces to which such tools are exposed.
Conventional power tool batteries are also configured such that the electronic contacts are adequately spaced apart to prevent an unintended connection between the contacts, resulting in a shorting out of the battery. Thus, another design criterion of the battery is to prevent an inadvertent electronic connection from being formed between the contacts on the battery.